- Data Brochure D 420 Boiler Reset Module 420 1 Information Brochure 2 Application Brochure Choose controls to match application 08/07 3 Design your mechanical applications Rough-in Wiring 4 5 Wiring Brochure Wiring and installation of specific control Rough-in wiring instructions Data Brochure Control settings and sequence of operation 6 Job Record Record settings & wiring details for future reference Introduction The Boiler Reset Module 420 provides outdoor reset to a hydronic heating sys
Table of Contents Table of Contents ...........................................................2 Outdoor Reset ...................................................... 12 Display and DIP Switches ..............................................2 Boiler Temperature Control .................................. 14 Dip Switch Settings ................................................2 tekmar Stager Operation ...................................... 17 Access Level ..................................................
Boil On-Off / Mod tekmar Stager / Off The Boil On-Off / Mod DIP switch selects whether the control operates an On-Off boiler or the firing rate of a Modulating boiler. Use the tekmar Stager / Off DIP switch when a tekmar staging control is be connected to the 420 in order to operate multiple boilers. A tekmar stager may include Boiler Controls 264, 265, and 268. • If set to Boil On-Off, the control operates an On-Off boiler. • If set to Mod, the control operates a Modulating boiler.
Display Symbols Description S Menu Field Item Field Displays the current menu Displays an abbreviated name of the selected item Status Field Number Field Displays the current status of the control’s inputs, outputs and operation. Most symbols in the status field are only visible when the VIEW Menu is selected Displays the current value of the selected item Symbols Description PUMP Displays when the primary or mixing pump is in operation. °F, °C, %, HOURS, MINUTES Units of measurement.
User Interface Adjusting a Setting Use the User Interface available on the Liquid Crystal Display (LCD) to setup and monitor the operation of the system. Use the four push buttons to the left of the LCD (Menu, Item, Up, Down) to select settings. As you enter settings, record the settings in the Job Record J 420. To adjust a setting: 1. Select the appropriate menu using the Menu button. 2. Select the item using the Item button. 3. Use the Up or Down button to make the adjustment.
Display Menus View Menu (1 of 1) The View menu items display the current operating temperatures and status information of the system. VIEW MENU Item Field Range Access Description -76 to 149°F (-60.0 to 65.0°C) InS Ad SECTION B OUTDOOR Current outdoor air temperature as measured by the outdoor sensor. -22 to 266°F (-30.0 to 130.0°C) InS Ad BOILER SUPPLY SECTION C Current boiler supply water temperature as measured by the boiler sensor.
Adjust Menu (1 of 3) The Adjust Menu items are the programmable settings used to operate the mechanical equipment. Item Field Range Access Description -60 to 45°F (-51.0 to 7.0°C) Default = 10°F (-12.0°C) InS Ad OUTDOOR DESIGN SECTION B The design outdoor air temperature used in the heat loss calculations for the heating system. Typically set to the temperature of the coldest day of the year.
Adjust Menu (2 of 3) Item Field Range Access Description Au, 2 to 42°F (Au, 1 to 23.5°C) Ad BOILER DIFFERENTIAL SECTION C The temperature differential that the control is to use when it is operating the boiler. Ad BOILER MOTOR SECTION C The amount of time required for the modulating actuating motor to fully open the gas valve or operate the fan speed from a stopped position to full speed on a modulating boiler.
Adjust Menu (3 of 3) Item Field Range 100 to 220°F (38.0 to 104.5°C) Default = 180°F (82.0°C) OFF, ON Default = OFF ADJUST MENU OFF, 1 (parallel, no priority) 2 (parallel, priority) 3 (pri-sec, no priority) 4 (Pri-sec, priority) Access Description Ad DHW EXCHANGE OCCUPIED SECTION F The minimum boiler target temperature to the DHW heat exchanger during the Occupied period. Note: This item is only available when DHW Mode is set 1 through 4.
Misc (Miscellaneous) Menu (1 of 1) The Miscellaneous Menu Items set control and display options such as access level and temperature units. MISC MENU Item Field Range Access Description InS (Installer) Ad (Advanced) InS Ad °F, °C Default = °F InS Ad UNITS Select temperature units between Fahrenheit and Celsius. 0 to 24 Ad BOILER BUS DEVICES Displays the number of devices on the boiler bus. OFF, SEL Ad FACTORY DEFAULT Loads the factory defaults when the Up and Down buttons are pressed.
To enable Max Heat: HAZARD Access to the Test button requires the removal of the front cover and exposes hazardous voltage while the control is powered. Only trained, qualified and competent personnel should operate the Test button. Test Press and hold the Test button for more than 3 seconds and less than 6 seconds. If there is a demand for heat, the ‘TEST’ and ‘MAX’ segments are displayed on screen and the control will turn on all outputs for up to 24 hours.
Test Wait 3 seconds Hold for 6 seconds Test Sequence of Operation tekmarNet®4 Communication Section A tekmarNet®4 (tN4) communicates between tN4 devices (thermostats, Reset Module and Expansion Modules). Each tN4 device is connected to a tN4 communication bus using two wires. Each tN4 bus adjusts a single water temperature in the system using indoor temperature feedback. The Boiler Reset Module 420 allows for one tN4 bus. This allows you to control a system with one water temperature.
Terminal Unit There is a terminal unit setting for each tN4 bus. The Terminal Unit setting is found in the Adjust menu. Hydronic Radiant Floor (1) Terminal type 1 is a heavy, or high mass, hydronic radiant floor system. This type of a hydronic radiant floor is embedded in either a thick concrete or gypsum pour. This heating system has a large thermal mass and is slow acting. Hydronic Radiant Floor (2) Terminal type 2 is a light, or low mass, hydronic radiant floor system.
Warm Weather Shut Down (WWSD) The Warm Weather Shut Down is the outdoor temperature at which hydronic heating is no longer required. The boiler operates only when a Domestic Hot Water (DHW) Demand or a Setpoint Demand is present. The WWSD setting is found in the Adjust menu. Boiler Terminal Unit Defaults When a terminal unit is selected for boiler zones, the control loads default values for the boiler design, boiler maximum supply, and boiler minimum supply temperatures.
Boiler Maximum The boiler maximum is the highest temperature that the control is allowed to use as a boiler target temperature. If the control does target the Boiler Maximum setting, and the boiler temperature is near the boiler maximum temperature, the maximum segment will be displayed in the LCD while either the boiler target temperature or the boiler temperature is being viewed. At no time does the control operate the boiler above 248°F (120.0°C). • Locate the Boiler Maximum setting in the Adjust menu.
0-10 V (dc) Example: A boiler requires a 1.8 V (dc) signal to fire the boiler at low fire. The boiler can be modulated to 10 V (dc) where it reaches high fire. This means the boiler’s input signal range is 1.8 to 10 V (dc). The 420 control has an output signal range of 0-10 V (dc). To make the two signal ranges the same, the Minimum Modulation required is: Boiler Range Control Range 18% 1.
To use the tekmar Staging operation, the following DIP switch settings are required: 1. Set the 420 Off / tekmar Stager DIP switch to tekmar Stager. 2. Set the 420 Boil On-Off / Mod DIP switch to Mod. The 420 boiler sensor must be located on the supply pipe leading from the boilers. On the Boiler Control 264, 265, or 268, the External Input / Stand Alone DIP switch must be set to External Input.
that the control provides DHW priority is reduced. Once the allowed time for priority has elapsed, the control overrides the DHW priority and resumes space heating. DHW Priority Override Time Increasing Time DHW MODE 2 - DHW in Parallel with Priority When a DHW Demand is present, the DHW Pump contact closes. The primary pump (P1) can operate when a boiler demand is present.
DHW with Low Temperature Boilers Section G If DHW heating is to be incorporated into a low temperature system such as a radiant floor heating system, a mixing device is often installed to isolate the high DHW supply temperature from the lower system temperature. If a mixing device is not installed, high temperature water could be supplied to the low temperature system while trying to satisfy the DHW demand. This may result in damage to the low temperature heating system.
Setpoint Mode 3 – Setpoint in Primary / Secondary Whenever a setpoint demand is present, the primary pump (P1) is turned on and the boiler is operated to maintain the setpoint target. Mode = 3 Setpoint Primary Pump Setpoint Priority Override Setpoint Priority Override applies to SETPOINT MODE 2 and MODE 4. To prevent the building from cooling off too much or the possibility of a potential freeze up during setpoint priority, the control limits the amount of time for setpoint priority.
Error Messages Local Errors and Device Errors Error messages are used to indicate a problem somewhere in the system. There are two types of error messages: Local Errors and Device Errors. A Local Error indicates an error specific to a device. For example, a thermostat with a sensor short circuit will show a Sensor Short Error on its display. No other devices will show this specific error (unless they also have a sensor short circuit).
Error Messages (1 of 2) Error Message Description ADJUST ERROR The control failed to read the Adjust menu settings, and reloaded the factory default settings. Operation stops until you check the Adjust menu settings. Note: To clear the error, the access level must be set to Advanced and the settings in the Adjust menu must be checked. MISCELLANEOUS ERROR The control failed to read the Miscellaneous menu settings, and reloaded the factory default settings.
Error Messages (2 of 2) Error Message Description OUTDOOR SENSOR OPEN CIRCUIT Due to an open circuit, the control failed to read the outdoor sensor. As a result, the control assumes an outdoor temperature of 32°F (0.0°C) and continues operation. Locate and repair the problem as described in the Data Brochure D 070. Once the error is corrected, press any button to clear the error. DEV SCHD The selected system schedule is no longer available.
Limited Warranty and Product Return Procedure Limited Warranty The liability of tekmar under this warranty is limited. The Purchaser, by taking receipt of any tekmar product (“Product”), acknowledges the terms of the Limited Warranty in effect at the time of such Product sale and acknowledges that it has read and understands same.
